1. Field of the Invention
The present invention relates to an improvement of an image forming apparatus including an image forming unit that forms an image with photographic quality on a recording medium conveyed from a sheet feeding unit.
2. Description of the Related Art
Conventionally, to obtain a desired glossy image with photographic quality by using an electrophotographic image forming apparatus, a special toner, a special recording medium, a special fixing device, and others have been tried to be used (refer to Japanese Patent Application Laid-Open No. 2002-341623 (hereinafter, “a first patent document”), Japanese Patent Application Laid-Open No. 2004-191678 (hereinafter, “a second patent document”), and Japanese Patent Application Laid-Open No. 2003-270991 (hereinafter, “a third patent document”).
For example, in the first patent document, a special toner is used for providing a gloss. After normal image formation on a sheet, a transparent toner is uniformly formed and fixed over the entire recording medium before being conveyed to a fixing unit, thereby obtaining photographic quality.
Also, in a technology typified by the second patent document, a special recording medium for providing a gloss is used. A thermoplastic resin layer is provided on a front or back of a recording medium. By further applying heat and pressure after an image is normally fixed, a uniform gloss can be achieved on the surface.
Furthermore, in the third embodiment, a special fixing device is used to provide a gloss. After a normal fixing process (first fixing), a second fixing unit formed of a smooth belt is provided to cool and is provided for cooling and peeling after a toner is again melted. With the use of the smoothness of the belt, a uniform gloss can be obtained.
However, the technology disclosed in the first patent document has problems in which a uniform transparent toner has to be always provided over the entire surface of the recording medium and a difference in toner thickness between an image part and a non-image part increases a load on the fixing unit. Moreover, to use the technology disclosed in the second patent document, its effect cannot be achieved until a special fixing device as explained in the third patent document. This poses problems in configuration, cost, power consumption, and others.